lib/qobj.c

   1 /*
   2  * Copyright (c) 2015-16  David Lamparter, for NetDEF, Inc.
   3  *
   4  * This file is part of Quagga
   5  *
   6  * Quagga is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2, or (at your option) any
   9  * later version.
  10  *
  11  * Quagga is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <zebra.h>
  22
  23 #include "thread.h"
  24 #include "memory.h"
  25 #include "hash.h"
  26 #include "log.h"
  27 #include "qobj.h"
  28
  29 static pthread_rwlock_t nodes_lock;
  30 static struct hash *nodes = NULL;
  31
  32 static unsigned int qobj_key (void *data)
  33 {
  34   struct qobj_node *node = data;
  35   return (unsigned int)node->nid;
  36 }
  37
  38 static int qobj_cmp (const void *a, const void *b)
  39 {
  40   const struct qobj_node *na = a, *nb = b;
  41   return na->nid == nb->nid;
  42 }
  43
  44 void qobj_reg(struct qobj_node *node, struct qobj_nodetype *type)
  45 {
  46   node->type = type;
  47   pthread_rwlock_wrlock (&nodes_lock);
  48   do
  49     {
  50       node->nid  = (uint64_t)random();
  51       node->nid ^= (uint64_t)random() << 32;
  52     }
  53   while (!node->nid || hash_get (nodes, node, hash_alloc_intern) != node);
  54   pthread_rwlock_unlock (&nodes_lock);
  55 }
  56
  57 void qobj_unreg(struct qobj_node *node)
  58 {
  59   pthread_rwlock_wrlock (&nodes_lock);
  60   hash_release (nodes, node);
  61   pthread_rwlock_unlock (&nodes_lock);
  62 }
  63
  64 struct qobj_node *qobj_get(uint64_t id)
  65 {
  66   struct qobj_node dummy = { .nid = id }, *rv;
  67   pthread_rwlock_rdlock (&nodes_lock);
  68   rv = hash_lookup (nodes, &dummy);
  69   pthread_rwlock_unlock (&nodes_lock);
  70   return rv;
  71 }
  72
  73 void *qobj_get_typed(uint64_t id, struct qobj_nodetype *type)
  74 {
  75   struct qobj_node dummy = { .nid = id };
  76   struct qobj_node *node;
  77   void *rv;
  78
  79   pthread_rwlock_rdlock (&nodes_lock);
  80   node = hash_lookup (nodes, &dummy);
  81
  82   /* note: we explicitly hold the lock until after we have checked the type.
  83    * if the caller holds a lock that for example prevents the deletion of
  84    * route-maps, we can still race against a delete of something that isn't
  85    * a route-map. */
  86   if (!node || node->type != type)
  87     rv = NULL;
  88   else
  89     rv = (char *)node - node->type->node_member_offset;
  90
  91   pthread_rwlock_unlock (&nodes_lock);
  92   return rv;
  93 }
  94
  95 void qobj_init (void)
  96 {
  97   if (!nodes)
  98     {
  99       pthread_rwlock_init (&nodes_lock, NULL);
 100       nodes = hash_create (qobj_key, qobj_cmp);
 101     }
 102 }
 103
 104 void qobj_finish (void)
 105 {
 106   hash_clean (nodes, NULL);
 107   hash_free (nodes);
 108   nodes = NULL;
 109   pthread_rwlock_destroy (&nodes_lock);
 110 }